Earth has undergone periodic climate shifts in the past, including four major ice ages.These consisting of glacial periods where conditions are colder than normal, separated by interglacial periods.

• 在最近的用法中，尤其是在一些环境政策中，“环境变化”这一术语通常仅指现代气候的变化，包括平均地表温度的升高，也就是熟知的全球变暖。